‘Kid Moses,’ by Mark R. Thornton

In the English-speaking world, “safari” evokes gaggles of sunburned tourists in pith helmets, gawking at lions and ­elephants from the safety of open-topped all-terrain vehicles before ending the day with gin and tonics and Instagrams of acacia trees silhouetted against fiery African sunsets. In Swahili, “safari” just means a trip, a plain old trip of any variety.

In his first novel, the American-born, Tanzania-based guide and conservationist Mark R. Thornton tells the story of Moses, a homeless boy from the big city, and his journey into the unknown world of his country’s wilderness. The book takes a steadfastly unromantic look at those stunning vistas in the unforgiving dry season, when “grass was tough and woody, the earth pale, the dust deep and fine,” when the land is “large and lonely,” anything but the “place of giraffes and sunsets, like in the storybooks.”

Nine-year-old Moses lives on the coast in Dar es Salaam, sharing quarters with other boys in the hull of an abandoned ship. He begs enough food to survive, along with the occasional cigarette to smoke or bit of glue to huff. Before his father died, he promised they would someday move to the country, where Moses dreams of riding a bicycle and having enough money to buy a soda now and again.

One day, Moses and his friend Kioso hide in the back of a truck headed out of town, a trip that ends quickly when Moses nearly gets Kioso killed by a debauched old white man. A few years later, Moses leads a second expedition, this time leaving behind the rural school where the two have landed and getting Kioso killed, once and for all, by a poisonous snake.

Thornton keeps an even tone with the kind of spare, austere language that reflects Moses’ stoic attitude and prevents the book from turning maudlin or crusading. On the opening pages and again when the action catches up to the deadly incident, he describes the skin of Kioso’s swollen leg as “tight and hard and its surface smooth, like the stomach bladder of a slaughtered goat.”

Along the way, Thornton introduces characters as varied as Tanzania’s polyglot mix of ethnic groups and religions: Mama Tesha, the shopkeeper; Hussein, with his shack full of cassettes; Boyd, the Great White Hunter; and the market bully, Prosper. With a kindly prostitute named Grace, her breasts like “large, smooth aubergines,” there’s a real fear that he’ll plummet into cliché. Yet he usually lands safely on the other side, lifted by his lack of condescension. His tone is neither patronizing nor idealizing. Rather, it resembles that of the fisherman who stares at Moses after pulling his dhow ashore, giving him “a look without judgment or shame or pity.”

If Thornton missteps, it’s in his eagerness to tell us what Moses doesn’t notice: “the rising of Jupiter” when he’s lost in the bush, the plants he doesn’t know are safe to eat, the bow and arrow he doesn’t realize he could fashion from a certain tree, the precise workings of the venom that kills Kioso.

Moses leads a difficult life, but he isn’t a victim. His own decisions carry him, and the doomed Kioso, into many of the worst situations he faces. Thornton gives him the animating gift of irrationality, of making decisions not even he understands, like stealing a watch he doesn’t want at the school for boys or wandering off from this safe haven because of his “nagging sense of urgency — he could never feel settled in a place so quiet and orderly.”

At one point, Moses finds a small river where he can swim alone. Submerged, where no one can hear him, he screams out everything he has kept inside. “He boxed, punched and fought an underwater war against even those who had helped him.” He’s a little boy with big contradictions, well worth following on his safari.

Nicholas Kulish, formerly the Nairobi ­correspondent for The Times, is now a ­correspondent in New York. He is the author of the novel “Last One In” and a co-author of the nonfiction book “The Eternal Nazi.”